Wireless spectrum is an expensive and valuable resource. In wide area network systems, e.g., cellular systems, wireless spectrum allocated to the WAN is, at times, less than fully utilized. It would be advantageous if methods and apparatus were developed which recognized and/or utilized such underutilized air link resources. For example, it would be beneficial if spectrum allocated or being used by a WAN could also be used for peer to peer communications in a way that does not significantly interfere with usage of the spectrum for WAN communications.